Journal of Self-Assembly and Molecular Electronics (SAME), 2013
This work is motivated by the original work of Guo et al. , which demonstrated the efficacy of SW... more This work is motivated by the original work of Guo et al. , which demonstrated the efficacy of SWNT electrodes for the study of charge transport through individual molecules. SWNTs are nearly ideal for this purpose. They are outstanding one-dimensional conductors, they can be linked to organic
DNA and DNA-based polymers are of interest in molecular electronics because of their versatile an... more DNA and DNA-based polymers are of interest in molecular electronics because of their versatile and programmable structures. However, transport measurements have produced a range of seemingly contradictory results due to differences in the measured molecules and experimental set-ups, and transporting significant current through individual DNA-based molecules remains a considerable challenge. Here, we report reproducible charge transport in guanine-quadruplex (G4) DNA molecules adsorbed on a mica substrate. Currents ranging from tens of picoamperes to more than 100 pA were measured in the G4-DNA over distances ranging from tens of nanometres to more than 100 nm. Our experimental results, combined with theoretical modelling, suggest that transport occurs via a thermally activated long-range hopping between multi-tetrad segments of DNA. These results could re-ignite interest in DNA-based wires and devices, and in the use of such systems in the development of programmable circuits.
In order to exploit the outstanding physical properties of one-dimensional (1D) nanostructures su... more In order to exploit the outstanding physical properties of one-dimensional (1D) nanostructures such as carbon nanotubes and semiconducting nanowires and nanorods in future technological applications, it will be necessary to organize them on surfaces with precise control over both position and orientation. Here, we use a 1D rigid DNA motif as a model for studying directed assembly at the molecular scale to lithographically patterned nanodot anchors. By matching the inter-nanodot spacing to the length of the DNA nanostructure, we are able to achieve nearly 100% placement yield. By varying the length of single-stranded DNA linkers bound covalently to the nanodots, we are able to study the binding selectivity as a function of the strength of the binding interactions. We analyze the binding in terms of a thermodynamic model which provides insight into the bivalent nature of the binding, a scheme that has general applicability for the controlled assembly of a broad range of functional nanostructures.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2011
Self-assembled DNA nanostructures can be used as scaffolds to organize small functional nanocompo... more Self-assembled DNA nanostructures can be used as scaffolds to organize small functional nanocomponents. In order to build working devices-electronic circuits, biochips, optical/photonics devices-controlled placement of DNA nanostructures on substrates must be achieved. Here we present a nanoimprint lithography-based process to create chemically patterned templates, rendering them capable of selectively binding DNA origami. Hexamethyldisilazane (HMDS) is used as a passivating layer on silicon dioxide substrates, which prevents DNA attachment. Hydrophilic areas, patterned by nanoimprint lithography with the same size and shape of the origami, are formed by selective removal of the HMDS, enabling the assembly of the origami scaffolds in the patterned areas. The use of nanoimprint lithography, a low cost, high throughput patterning technique, enables high precision positioning and orientation of DNA nanostructures on a surface over large areas.
Here we present a simple approach for the controlled formation of one-dimensional and multitermin... more Here we present a simple approach for the controlled formation of one-dimensional and multiterminal nanotube junctions. We describe a facile bottom-up strategy for joining the ends of single-walled carbon nanotubes. The geometry of the junctions can be varied and controlled by linker-induced assembly of DNAwrapped nanotubes.
A key impediment to the implementation of a nanoelectronics technology based on single wall carbo... more A key impediment to the implementation of a nanoelectronics technology based on single wall carbon nanotubes (SWCNTs) is the inability to arrange them in a manner suitable for integration into complex circuits. As a step toward addressing this problem, we explore the binding of fixed-length, end-functionalized SWCNT segments to lithographically defined nanoscale anchors, such that individual SWCNTs can be placed with control over position and orientation. Both monovalent and bivalent bindings are explored using covalent and noncovalent binding chemistries. Placement efficiency is assessed in terms of overall yield of SWCNT binding, as well as binding specificity and the degree of nonspecific binding. Placement yields as high as 93% and 79% are achieved, respectively, for covalent binding and for binding through DNA hybridization. Orientational control of the SWCNT segments is achieved with 95% and 51% efficiency for monovalent and bivalent bindings, respectively. This represents a n...
Journal of Self-Assembly and Molecular Electronics (SAME), 2013
This work is motivated by the original work of Guo et al. , which demonstrated the efficacy of SW... more This work is motivated by the original work of Guo et al. , which demonstrated the efficacy of SWNT electrodes for the study of charge transport through individual molecules. SWNTs are nearly ideal for this purpose. They are outstanding one-dimensional conductors, they can be linked to organic
DNA and DNA-based polymers are of interest in molecular electronics because of their versatile an... more DNA and DNA-based polymers are of interest in molecular electronics because of their versatile and programmable structures. However, transport measurements have produced a range of seemingly contradictory results due to differences in the measured molecules and experimental set-ups, and transporting significant current through individual DNA-based molecules remains a considerable challenge. Here, we report reproducible charge transport in guanine-quadruplex (G4) DNA molecules adsorbed on a mica substrate. Currents ranging from tens of picoamperes to more than 100 pA were measured in the G4-DNA over distances ranging from tens of nanometres to more than 100 nm. Our experimental results, combined with theoretical modelling, suggest that transport occurs via a thermally activated long-range hopping between multi-tetrad segments of DNA. These results could re-ignite interest in DNA-based wires and devices, and in the use of such systems in the development of programmable circuits.
In order to exploit the outstanding physical properties of one-dimensional (1D) nanostructures su... more In order to exploit the outstanding physical properties of one-dimensional (1D) nanostructures such as carbon nanotubes and semiconducting nanowires and nanorods in future technological applications, it will be necessary to organize them on surfaces with precise control over both position and orientation. Here, we use a 1D rigid DNA motif as a model for studying directed assembly at the molecular scale to lithographically patterned nanodot anchors. By matching the inter-nanodot spacing to the length of the DNA nanostructure, we are able to achieve nearly 100% placement yield. By varying the length of single-stranded DNA linkers bound covalently to the nanodots, we are able to study the binding selectivity as a function of the strength of the binding interactions. We analyze the binding in terms of a thermodynamic model which provides insight into the bivalent nature of the binding, a scheme that has general applicability for the controlled assembly of a broad range of functional nanostructures.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2011
Self-assembled DNA nanostructures can be used as scaffolds to organize small functional nanocompo... more Self-assembled DNA nanostructures can be used as scaffolds to organize small functional nanocomponents. In order to build working devices-electronic circuits, biochips, optical/photonics devices-controlled placement of DNA nanostructures on substrates must be achieved. Here we present a nanoimprint lithography-based process to create chemically patterned templates, rendering them capable of selectively binding DNA origami. Hexamethyldisilazane (HMDS) is used as a passivating layer on silicon dioxide substrates, which prevents DNA attachment. Hydrophilic areas, patterned by nanoimprint lithography with the same size and shape of the origami, are formed by selective removal of the HMDS, enabling the assembly of the origami scaffolds in the patterned areas. The use of nanoimprint lithography, a low cost, high throughput patterning technique, enables high precision positioning and orientation of DNA nanostructures on a surface over large areas.
Here we present a simple approach for the controlled formation of one-dimensional and multitermin... more Here we present a simple approach for the controlled formation of one-dimensional and multiterminal nanotube junctions. We describe a facile bottom-up strategy for joining the ends of single-walled carbon nanotubes. The geometry of the junctions can be varied and controlled by linker-induced assembly of DNAwrapped nanotubes.
A key impediment to the implementation of a nanoelectronics technology based on single wall carbo... more A key impediment to the implementation of a nanoelectronics technology based on single wall carbon nanotubes (SWCNTs) is the inability to arrange them in a manner suitable for integration into complex circuits. As a step toward addressing this problem, we explore the binding of fixed-length, end-functionalized SWCNT segments to lithographically defined nanoscale anchors, such that individual SWCNTs can be placed with control over position and orientation. Both monovalent and bivalent bindings are explored using covalent and noncovalent binding chemistries. Placement efficiency is assessed in terms of overall yield of SWCNT binding, as well as binding specificity and the degree of nonspecific binding. Placement yields as high as 93% and 79% are achieved, respectively, for covalent binding and for binding through DNA hybridization. Orientational control of the SWCNT segments is achieved with 95% and 51% efficiency for monovalent and bivalent bindings, respectively. This represents a n...
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Papers by Erika Penzo